Late clinical evaluation was performed on 39 patients who had repair of incomplete persistent atrioventricular canal at the NIH prior to 1976. Average follow up duration is 13 (rance 5-24) years. Twenty-six patients are asymptomatic at their most recent evaluation. Actuarial survival is 88 plus or minus 6% at 13 years after operation; survival without reoperation is 82 plus or minus 6%. However, survival free of any late complications, including late death, reoperation, arrhythmia, or symptomatic mitral regurgitation is 52 plus or minus 10% at 13 years.